RESUMO
BACKGROUND: Response Evaluation Criteria in Solid Tumors (RECIST)-defined measurements are limited when evaluating soft tissue sarcoma (STS) response to therapy. Histopathological assessment of STS response requires a determination of necrosis following resection. A novel semi-automated technique for volumetric measurement of tumor necrosis, using enhanced magnetic resonance imaging (CE-MRI), is described. PATIENTS AND METHODS: Eighteen patients with STS were treated with neoadjuvant therapy and then resected. CE-MRI, obtained prior to resection, were evaluated by two observers using semi-automated segmentation. Tumor volume and percent necrosis was compared with histology and RECIST measurements. RESULTS: The median percent necrosis, determined histologically and from CE-MRI, was 71.9% and 67.8%, respectively. Accuracy of these semi-automated measurements was confirmed, being statistically similar to those obtained at histopathological assessment of the resected tumor. High Intra-class correlation co-efficients suggest good inter-observer reproducibility. Tumor necrosis did not correlate with the RECIST measurements. CONCLUSION: Semi-automated determination of tumor volume and necrosis, using CE-MRI, is suggested to be accurate and reproducible.